Reprinted from the BOTANICAL Gazette, 6o: No. I, July 1915 



BOW- 



THE EFFECTS OF ILLUMINATING GAS UN QM 



ROOT SYSTEMS 



CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY 205 



Ed ward M. Harvey and R. Catlin Rose 



(WITH NINE FIGURES) 



Introduction 



The injurious effects of illuminating gas upon trees and shrubs 

 have been testified to by numerous observers. In 1864 Girardin 

 (5) reported severe injuries to trees in several cities of Germany 

 which he attributed to escaping illuminating gas. Similar observa- 

 tions have since been recorded by many writers, among whom are 

 Virchow (17), Kny (8), Spath and Meyer (14), Eulenberg (4), 

 Wehmer (18), Shonnard (13), and others. 



The shade tree commissions of every city find themselves face 

 to face with this serious problem. The trees of our city streets and 

 parks are unusually subject to the various tree-injuring agencies, 

 the chief of which are insects, fungi, and atmospheric and soil 

 impurities. The two latter factors are particularly characteristic 

 of the troubles of city trees. The problem of gas injuries, 

 therefore, is one of considerable economic importance. City 

 foresters should know the exact cause of any tree death, not 

 only to enable them to provide means for future protection, but 

 also in 'order to determine with whom responsibility rests for the 

 present financial losses. They should therefore be able to say 

 with certainty whether or not a tree has been killed by gas in 

 the soil. At present this is no small undertaking, because there 

 are few, if any, reliable symptoms known by which one may differ- 

 entiate with certainty gas injuries from those clue to several other 

 causes. For example, fungi sometimes quickly become prom- 

 inent in a tree injured by gas, as purely a secondary effect (see 

 , _K\v 8 and Stone 15); but in a case like this the primary injury 

 Jjmight easily be attributed to the fungi. It is claimed that char- 

 "" acteristic odors often accompany gas poisonings; sometimes in the 

 27] [Botanical Gazette, vol. 60 



